Insulating doors are generally known and commonly use a foam core as disclosed in U.S. Patent No. 4,716,700 to Hagemeyer, and U.S. Pat. No. 3,950,894 to DiMaio. These doors, however, are typically not suitable for industrial applications in areas of high traffic flow. Both disclosed doors achieve a seal by closing against a gasketed door jamb. This permits them to open only in one direction, making them unsuitable where freely swinging doors are required.
Leaf-style weather stripping is disclosed in U.S. Pat. No. 4,716,700 to Hagemeyer but such weather stripping as disclosed is inadequate to seal a two-way swinging door. The disclosed weather strip is used at the bottom of the door only. The leaf is held away from the door by a bracket which would present a danger of injury if used on the swinging vertical edge of the door where hands might encounter it. Also, such a bracket is susceptible to breakage if used in an industrial area where carts frequently pass through the door.
One prior swinging door system utilizes a pair of swinging doors. Each door has a thick insulated core section with surface sheets laminated on opposite faces thereof. The surface sheets extend beyond the core in all directions, forming a peripheral gap. An elongated edge cap fills the gap and covers the peripheral edge of the door. The edge cap has a rectangular plug section which extends into the gap between the flanges formed by the surface sheet, and has an outer semicircularly curved portion which forms a bullnose at the edge of the door. The curved portion has a width equal to the overall thickness of the door, whereby a smoothly rounded transition occurs from one side of the door around the edge to the other side of the door. A primary disadvantage of this design is that it requires close tolerances in order to avoid gaps between the edge of the surface sheets and the rounded portion of the edge cap. Also, the edge cap tends to pull free from the door after repeated impact.
Another known insulating door employs an insulated core panel having an elongated rectangular groove formed in the median of the edge of the insulating panel. The core panel is protected by surface sheets. The edge of each surface sheet effectively wraps around an edge of the core panel and is received in the rectangular groove formed therein. A gap remains in the rectangular groove between the inserted surface sheet edges. A flexible blade gasket is inserted in this gap. The inserted portion of the gasket is of check-mark cross section so that it is easier to insert it than to remove it. However, this design does not effectively resist removal when substantial force is employed, as may occur in high traffic industrial areas.
Another known insulated laminated door accommodates an edge gasket by different means. The edge of the door panel of this door is provided with a narrow median gap which communicates with a larger cylindrical cavity formed in the insulated core of the door. The cavity runs along the edge of the door just beneath the edge surface. A flexible gasket having a bead on one edge which is wider than the median gap of the door is received by the cylindrical cavity. The blade portion of the gasket passes through the gap and extends distally from the edge of the door. This door design is difficult to form.
Therefore, a need exists for an improved door construction and method of making doors, particularly insulating type industrial doors.